Sealing sleeve of elastic material

ABSTRACT

A sealing sleeve made from elastic material, particularly for sealing the gap between a joint part and a shaft in rapidly rotating, so-called homo-kinetic joints, in which the inner ring of the sealing sleeve abuts sealingly against the shaft and the outer ring against a joint part, whereby the outer ring and the inner ring are connected with each other by a conically constructed ring diaphragm which is deformable into a roller bellows in the installed position.

I United States Patent 1191 1111 3,707,852 Burckhardt et al. 14 1 Jan.2, 1973 [54] SEALING SLEEVE OF ELASTIC [56] References Cited MATERIALUNITED STATES PATENTS [75] Inventors: Manfred ll. Burckhardt, Waiblin-2,781,649 2/1957 Stahl et al ..64/32 X smtgan'nad 3,260,071 7/1966Westercamp.... ..64/32 Cannstatt, Gemany 3,468,171 9/1969 Macielinski..74/1s.1 [73] Assignee: Daimler-Benz Aktiengesellschaft,

- Stuttgart-Unterturkheim, German Primary Exammer-M1lton Kaufman Filed p27 1968 Attorney-Craig, Antonelli & Hill [21] App]. No.: 763,274 [57]ABSTRACT A sealing sleeve made from elastic material, particu- [30]Foreign Application Priority Data larly for sealing the gap between ajoint part and a shaft in rapidly rotating, so-called homo-kineticjoints, Sept. 28, 1967 Germany ..P 16 25 974.8 in which the inner g ofthe Sealing sleeve abuts [52] us CL 64/32 F 74/18 1 277/205 sealinglyagainst the shaft and the outer ring against a 51 Int.c1...111:1:111:11: "f .F l6d 3/84 whereby the ring and innering [58]Field ofSearch....64/32, 32 F; 74/181; 277/205 are cmmected with each bya structed ring diaphragm which is deformable into a roller bellows inthe installed position.

"PATENTEDJANZ ms 3.707.852

nwmons MANFRED H BURCKHARDT LUTZ SCHAFER BY 6 P ATTORNEYS SEALING SLEEVEOF ELASTIC MATERIAL The present invention relates to a sealing sleeve ofelastic material, especially for sealing the gap between the joint partand the shaft of rapidly rotating, so-called homokinetic joints, whichconsists of an inner ring and of an outer ring abutting in sealingrelationship against the shaft and against the joint part, respectively.

Roller-type bellows have been used heretofore for sealing such types ofjoints. These roller-type bellows are basically manufactured andvulcanized in the usually rounded-off or curved configuration, in whichthey are inserted during the operation. The prior art types of seals,however, entail the disadvantage that the pre-set rounding-off opposesany rolling motion by reason of the stresses occurring thereby whichleads to a cross-fold formation during an angular deflection of thejoint at those places which are disposed in a plane extending at anangle displaced by 90 to the angular deflection plane. In case ofcontact of the folds or pleats with a place of the joint or in case ofmutual contact, the roller bellows abrades and wears rapidly.Additionally, the stresses during high rotational speeds of about 6,000to 7,000 rpm. lead to endurance failures in the roll radius. I

The present invention aims at creating a sealing sleeve which avoidsthese disadvantages and more fully satisfies the requirements especiallywith rapidly rotating, homokinetic joints. The present inventionessentially consists in that the outer ring and the inner ring of thesealing sleeve are connected with each other by a conically shaped ringdiaphragm which is deformable into a roller-type bellows only in theinstalled position. The roll radius, which forms itself in the installedcondition, is thereby able to form at any suitable place correspondingto the given angular deflection with constant pre-stress. Additionally,the stress directions within the diaphragm are maintained so that theendurance limit and fatigue strength are increased.

The usual roller-type bellows are so installed into the joints that theconcave side thereof is directed outwardly. During heating-up of thejoint, the roller bellows may snap outwardly as a result of the excesspressure then occurring on the inside, whereby it bursts as a rule. Inorder to avoid this disadvantage, provision may be made according to thepresent invention that the concave side of the roller bellows indirected inwardly. With such an arrangement, the roller bellows isstressed only in tension also in the presence of an internal excesspressure, which leads to stable equilibrium conditions.

An extraordinarily advantageous type of construction of a sealing sleeveis obtained in accordance with the present invention if the cone angleof the annular diaphragm amounts to between 30and 50. The displacementof the roll radius as a result of the centrifugal force of the rollerbellows and of the liquid lubricant at higher speeds is properly takeninto consideration thereby as it is also assured simultaneously thatwith the usual deflection angles of the joint, the opposite side of theroller bellows still possesses a roll radius.

The formation of the roller bellows can also be realized by inverting oraxially displacing the outer ring. With this construction, a largerroll-range results because the counter-bending forces resulting from theoverturning or inverting can be absorbed directly at the securing placeat the joint part whereas with the other types of constructions, thecounter-bending forces have to be absorbed by the diaphragm on the sideof the shaft. Provision may also be made advantageously that the outerring is secured on the outside of the joint part by means of a clampingring.

Accordingly, it is an object of the present invention to provide asealing sleeve of elastic material, particularly for homokinetic joints,which avoids by simple means the aforementioned shortcomings anddrawbacks encountered heretofore in the prior art.

Another object of the present invention resides in a sealing sleeve ofelastic material which minimizes the danger of wear and endurancefailures while at the same time increases the fatigue limit.

A further object of the present invention resides in a sealing sleeve,particularly for homokinetic joints, which avoids the danger ofbursting, particularly under high rotational speeds while assuringstable equilibrium conditions under all operating conditions.

These and further objects, features, and advantages of the presentinvention will become more obvious from the following description whentaken in connection with the accompanying drawing which shows, forpurposes of illustration only, several embodiments in accordance withthe present invention, and wherein:

FIG. 1 is an axial cross-sectional view through a sealing sleeve made inaccordance with the present invention in its unstressed or relievedcondition prior to installation;

FIG. 2 is a somewhat schematic view of the sealing sleeve according toFIG. 1 installed into a joint;

FIG. 3 is a cross-sectional view through the sealing sleeve of FIG. 2with the joint angularly deflected; and

FIGS. 4 through 7 are partial cross-sectional views, on a reduced scale,of several embodiments of installation arrangements of sealing sleevesin accordance with the present invention.

1 Referring now to the drawing wherein like reference numerals are usedthroughout the various views to designate like parts, with the sealingsleeve of the present invention generally designated by referencenumeral 1 according to FIGS. 1 and 2, the manufactured or vulcanizedshape thereof is separate and distinct from the installed shape. Thesealing sleeve 1 is, as can be seen from FIG. 1, so heated (vulcanized)that the inner ring 2 and the outer ring 3 are connected with each otherby a conical annular diaphragm 4 under a cone angle a of about 30 50 toa line perpendicular to the axis. During the installation according toFIG. 2, for

example, the inner ring 2 is axially displaced or in verted toward theinside and is enlarged and drawn over ashaft 5. The outer ring 3 issecured at the joint part 6. The roll-radius generally designated byreference numeral 7 and illustrated in FIG. 2 is formed thereby. Duringan angular deflection of the joint up to the usually maximum possibleangle [3 of 8, the rollradius 7' moves without noticeable change of thestress and without the formation of cross folds or pleats toward theplace conditioned by the angular deflection, as indicated in dash linein FIG. 3.

The optimum cone angle is dependent, on the one hand, from therotational speed and therewith the centrifugal force of the rollerbellows and from the heating-up of the joint which brings about aninternal excess pressure and, on the other, from the required deflectionangle. With higher rotational speeds, up to about 7,000 rpm. theroll-radius 7' is displaced outwardly by the influence of thecentrifugal force of the sealing sleeve 1 and of the liquid lubricant,as indicated in dash line in FIG. 2.

In the thus resulting end position, the outside of the diaphragm shouldmove at most up to the axial position as otherwise bending-stressendurance failures result from an excessive stretching of the clampingplace, above all, with an angularly deflected joint. With the differentsecuring possibilities which are illustrated in the embodimentsaccording to FIGS. 4 to 7, a larger buckling of the diaphragm could leadto contact with the outer parts of the joint part 6 and therewith tochaffing and wear which would have as a consequence the destruction ofthe sealing sleeve 1. For that reason, the cone angle a should possiblynot exceed 50 during the manufacture of the sealing sleeve 1. If thecone angle is kept smaller than 30, then the roller bellows is pulledcompletely straight at the side opposite the deflection angle, dependenton the deflection angle of the joint. No roll-radius could then form anylonger. If additionally an axial displaceability of the joint isrequired, then the cone angle a has to be increased againcorrespondingly.

In summary, it may be stated that the higher the rotational speed of thesealing sleeve 1, the smaller should be the cone angle a. With a largerdeflection angle of the joint and with larger axial displaceability, thecone angle a, however, hasto be increased again. The optimum for both ofthese contradictory requirements lies approximately in the middle with acone angle a of 40.

The sealing sleeve 1 is assembled with a pre-stress, as illustrated inFIG. 1, in that the inner ring 2 is enlarged. The formation of theroll-radius 7 can take place by axially displacing or inverting of theinner ring 2 or of the outer ring 3 either at the shaft or at the jointpart 6. In case of inverting or axially displacing the inner ring 2, thesecuring of the sealing sleeve 1 at the joint part 6 may be realized insuch a manner that the outer ring 3 is vulcanized, glued or bonded inany conventional manner to the sheet metal pot of the joint part 6 (FIG.4).

The embodiment according to FIG. 5 shows a cliptype fasteningarrangement inwardly at the sheet metal pot of the joint part 6 wherebythe inner ring 2 is also inverted or overturned on the shaft 2. Withthis type of securing, the outer ring 3 is reinforced by a sheet metalmember 8, preferably vulcanized into the outer ring and snaps-in with abead thereof over a flange portion of sheet metal part 6 from theinside.

In the embodiment according to FIG. 6, a clip-type fastening arrangementof the outer ring at the sheet metal pot of the joint part 6 is alsoprovided in which the outer ring snaps-in with a bead thereof over aflange portion of sheet metal part 6 from the outside. For that purpose,the outer ring is provided with rubber beads 9 which snap over a flangededge of the sheet metal pot 6. Also, in this case a sheet metal ring 10is provided for the reinforcement. For the purpose of a better seal incase of excess pressures by reason of higher rotational speeds, asealing lip of conventional construction may also be added.

In the embodiment according to FIG. 7, the outer ring consistingessentially of a bead 11 is overturned or inverted inwardly (1l'-ll) andis secured on a flanged edge of the sheet metal pot of the joint part 6by means of a clamping ring 12. With this type of inverting, a largerroll-range results because the counter-bending forces of the invertingaction can be directly absorbed in the clamp means whereas the invertingwith the other embodiments has to be absorbed by the diaphragm 4 on theside of the shaft.

While we have shown and described several embodiments in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown to a person skilled in the art, and we therefore do not wish to belimited to the details shown and described herein, but intend to coverall such changes and modifications as are within the scope of thoseskilled in the art.

It is claimed 1. A gasket-type sealing arrangement comprising: twomutually movable parts including a joint section and a shaft with a gaptherebetween, which rotate together, a gasket of elastic material havingan inner ring portion and an outer ring portion installed between saidmutually movable parts and contacting said shaft and joint section,respectively, and further having the shape of a roller bellowsconnecting said inner and outer ring portions, said gasket formed of anannular membrane which is pre-stressed so that the membrane seeks toassume a conical shape, and said ring portions positioned to hold saidmembrane from its unstressed conical shape.

2. A sealing arrangement gasket is directed toward the side of the jointto be sealed.

3. A sealing arrangement according to claim 2, wherein the cone angle ofthe membrane amounts to about 30 to 50.

4. A sealing arrangement according to claim 3, wherein the formation ofthe roller bellows is created by the displacement of said inner ringportion along the axis of said shaft.

5. A sealing arrangement according to claim 4, wherein the outer ringportion is secured at the joint section on the side thereof facing saidshaft.

6. A sealing arrangement according to claim 4, wherein the outer ringportion is secured on the outside of the joint section.

7. A sealing arrangement according to claim 3, wherein the formation ofthe roller bellows is realized by an inverting bead provided at theouter ring portion.

8. A sealing arrangement according to claim 7, wherein said beadprovided at'the outer ring portion is secured on the outside of thejoint section by a clampmg ring.

9. A sealing arrangement according to claim 1, wherein the cone angle ofthe deformable membrane amounts to about 30 to 50.

10. A sealing arrangement according to claim 1, wherein the formation ofthe roller bellows is created by the displacement of said inner ringportion along the axis of said shaft.

11. A sealing arrangement according to claim 10,

wherein the outer ring portion is secured at the joint section on theinside thereof.

it: k =0:

1. A gasket-type sealing arrangement comprising: two mutually movableparts including a joint section and a shaft with a gap therebetween,which rotate together, a gasket of elastic material having an inner ringportion and an outer ring portion installed between said mutuallymovable parts and contacting said shaft and joint section, respectively,and further having the shape of a roller bellows connecting said innerand outer ring portions, said gasket formed of an annular membrane whichis pre-stressed so that the membrane seeks to assume a conical shape,and said ring portions positioned to hold said membrane from itsunstressed conical shape.
 2. A sealing arrangement gasket is directedtoward the side of the joint to be sealed.
 3. A sealing arrangementaccording to claim 2, wherein the cone angle of the membrane amounts toabout 30* to 50*.
 4. A sealing arrangement according to claim 3, whereinthe formation of the roller bellows is created by the displacement ofsaid inner ring portion along the axis of said shaft.
 5. A sealingarrangement according to claim 4, wherein the outer ring portion issecured at the joint section on the side thereof facing said shaft.
 6. Asealing arrangement according to claim 4, wherein the outer ring portionis secured on the outside of the joint section.
 7. A sealing arrangementaccording to claim 3, wherein the formation of the roller bellows isrealized by an inverting bead provided at the outer ring portion.
 8. Asealing arrangement according to claim 7, wherein said bead provided atthe outer ring portion is secured on the outside of the joint section bya clamping ring.
 9. A sealing arrangement according to claim 1, whereinthe cone angle of the deformable membrane amounts to about 30* to 50*.10. A sealing arrangement according to claim 1, wherein the formation ofthe roller bellows is created by the displacement of said inner ringportion along the axis of said shaft.
 11. A sealing arrangementaccording to claim 10, wherein the outer ring portion is secured at thejoint section on the inside thereof.